Terry Pratchett takes Shakespeare’s Macbeth and then turns it up till the knob comes off.  It’s all there – a wicked duke and duchess, the ghost of the murdered king, dim soldiers, strolling players, a land in peril. Who stands between the Kingdom and destruction?  Three witches: Granny Weatherwax (intolerant, self-opinionated, powerful), Nanny Ogg (down-to-earth, vulgar) and Magrat Garlick (naïve, fond of occult jewelry and bunnies). Friday – Saturday at 8 p.m.; Sunday at 2:30 p.m.